P5/P6 Math: Cutting into pieces with a tool

The question below requires students to see that one cut can cut a single length into 2 pieces.
And 2 cuts into 3 pieces.

Such questions are common in Paper 1 of P5 and P6 exams.
Calculator usage is not allowed.

Questions of a similar nature can be also found here.

A carpenter using a hacksaw can saw a length of wood into 3 pieces in 3 minutes.
How long will it take for the carpenter to saw the same length of wood into 9 pieces?
(*Hint* The answer is not 9 minutes.) 

A Hacksaw



If the above question is easy, try to do the more challenging question below.

The question below will randomize with different numbers every hour. 
Copy below question down before making attempt.